Cell transport

• What is active transport

  Molecules are moved across a membrane against the concentration gradient, this uses energy
• equation for surface area of 1 side

  2x2 =4
• Equation for total surface area e.g

  6x4 =24
• Equation for volume e.g

  2x2x2 =8
• What do exchange surfaces need to have

  Thin/short diffusion distance

  Large concentration gradient

  Large surface area
• What is osmosis

  movement of water from an area of high water potential to an area of low water potential across a partially permeable membrane
• What affects osmosis

  Concentration gradients of water, temperatures, pressure, surface area
• What affects active transport

  Energy availability, temperature, amount of carrier proteins
• What affects diffusion

  Concentration gradient, temperature, surface area
• What is diffusion

  movement of particles (like molecules or ions) from an area of high concentration to an area of low concentration, without requiring energy